Add support for (de)serializing LayerSelection.

cc/input/layer_selection_bound_unittest.cc

Index: cc/input/layer_selection_bound_unittest.cc
diff --git a/cc/input/layer_selection_bound_unittest.cc b/cc/input/layer_selection_bound_unittest.cc
index 53f3ac1b8bd434abda5fa94ac0990a07acb80785..b9f77cee0ca5ac2cc916aa10e0a41d51f73f0f45 100644
--- a/cc/input/layer_selection_bound_unittest.cc
+++ b/cc/input/layer_selection_bound_unittest.cc
@@ -34,5 +34,39 @@ TEST(LayerSelectionBoundTest, AllTypePermutations) {
   VerifySerializeAndDeserializeProto(bound);
 }
 
+void VerifySerializeAndDeserializeLayerSelectionProto(

[vmpstr, 2015/12/18 07:50:02]

Move this after the other function above please. I kind of prefer having
functions followed by tests... But this isn't a strong suggestion, so if you
prefer this way it's fine too.

[nyquist, 2015/12/18 18:54:35]

Done.

+    const LayerSelection& selection1) {
+  proto::LayerSelection proto;
+  LayerSelectionToProtobuf(selection1, &proto);
+  LayerSelection selection2;
+  LayerSelectionFromProtobuf(&selection2, proto);
+  EXPECT_EQ(selection1, selection2);
+}
+
+TEST(LayerSelectionTest, AllSelectionPermutations) {
+  LayerSelectionBound start;
+  start.type = SelectionBoundType::SELECTION_BOUND_LEFT;
+  start.edge_top = gfx::Point(3, 14);
+  start.edge_bottom = gfx::Point(6, 28);
+  start.layer_id = 42;

[vmpstr, 2015/12/18 07:50:02]

blank after this line please

[nyquist, 2015/12/18 18:54:35]

Done.

+  LayerSelectionBound end;
+  end.type = SelectionBoundType::SELECTION_BOUND_RIGHT;
+  end.edge_top = gfx::Point(14, 3);
+  end.edge_bottom = gfx::Point(28, 6);
+  end.layer_id = 24;

[vmpstr, 2015/12/18 07:50:02]

blank after this line please

[nyquist, 2015/12/18 18:54:35]

Done.

+  LayerSelection selection;
+  selection.start = start;
+  selection.end = end;
+  selection.is_editable = true;
+  selection.is_empty_text_form_control = true;

[vmpstr, 2015/12/18 07:50:02]

blank after this line please

[nyquist, 2015/12/18 18:54:35]

Done.

+  VerifySerializeAndDeserializeLayerSelectionProto(selection);
+  selection.is_empty_text_form_control = false;
+  VerifySerializeAndDeserializeLayerSelectionProto(selection);
+  selection.is_editable = false;
+  VerifySerializeAndDeserializeLayerSelectionProto(selection);
+  selection.is_empty_text_form_control = true;
+  VerifySerializeAndDeserializeLayerSelectionProto(selection);
+}
+
 }  // namespace
 }  // namespace cc